As is known, known welding machines comprise a welding unit having a number of electric connectors supplied with a predetermined welding voltage/current; and a hand-held welding tool defined by a welding gun or torch and connected electrically by a power cable to the electric connectors on the welding unit, which supplies it with the voltage/current by which to generate the electric welding arc.
More specifically, the welding unit of the welding machine normally comprises an electric power module for supplying the external connectors with welding voltage/current; a wire-feed assembly for supplying the welding wire instant by instant, if the MIG or MAG welding process is selected; a bottle containing a mixture of gases supplied by conduits to a diffuser integrated in the torch; and a cooling unit also connected to the torch by conduits to cool both the torch body and the relative power cable.
More specifically, the cooling unit comprises a cooling circuit; a coolant tank; a radiator for outwardly releasing the heat accumulated by the coolant; and an electrically powered hydraulic pump for circulating the coolant in the cooling circuit.
Some known welding machines of the above type have a highly “compact” structure, in which all the above component parts are integrated and assembled inside a single protective casing. In such welding machines, each of the above component parts is therefore “integrated” stably and permanently inside the protective casing.
Welding machines of the above type, in which the welding unit has a “compact” integrated structure, are extremely practical, by being easy to carry and transport, and by eliminating external bulk in the form of electric cables or hydraulic conduits connecting the various component parts. In such welding machines, in fact, all the electric and hydraulic connections between the various units and modules are made at the assembly stage, thus making the machine extremely safe, both electrically, by preventing the operator from accidentally coming into contact with the electric cables, and as regards correct connection.
On the other hand, maintenance of the cooling unit of “compact” welding machines of the type described above is extremely awkward. That is, because of the extremely small amount of space between the electric cables and the highly electrically conductive component parts or conduits of the cooling circuit, repair of individual component parts of the cooling unit is extremely complicated and dangerous.
Any maintenance or repair of the cooling unit therefore calls for skilled technicians qualified to work in high-risk, electric discharge environments, thus increasing the cost of servicing and repairing the machine.
Moreover, to service or repair the cooling unit, the welding unit in some cases must be sent to specialized service facilities, thus resulting in prolonged downtime and a serious reduction in output.
To eliminate the above drawbacks, it has been proposed to separate the cooling unit from the welding unit by locating it outside the protective casing, so that it is independent of the other component parts inside the welding unit and therefore easier to service or repair. An external cooling unit comprises a number of electric and hydraulic connectors, which, when the welding machine is installed, are connected by electric cables and external cooling conduits to corresponding electric and hydraulic connectors on the power module and torch respectively.
Though simplifying maintenance of the cooling unit, the above solution also has several drawbacks.
In particular, installation of a welding machine with a separate cooling unit calls for skilled labour to connect the external cooling unit electrically and hydraulically to the component parts on the welding unit, thus increasing the installation cost of the welding unit. Moreover, the wiring and conduits outside the protective casing of the welding unit make the welding machine extremely bulky, awkward to carry, and electrically hazardous.
Finally, the external connectors and connecting cables of the cooling unit are extremely expensive, by having to conform with electric safety regulations, and so greatly increase the overall production cost of the welding machine.